An X-ray detector included in a conventional X-ray Computed Tomography (CT) apparatus includes a photodiode array in which a plurality of active areas are formed. To uniformly detect X-rays radiated by an X-ray tube, the active areas are arranged at regular intervals. In this situation, the expression “intervals between the active areas” denotes the intervals recognised when the conventional X-ray CT apparatus reconstructs projection data.
The photodiode array is manufactured by cutting out silicon wafer having the active areas formed on a surface thereof. During the process of cutting out the silicon wafer however, very small cracks may occur in end parts of the silicon wafer. Further, in the surrounding areas of the active areas, for example, wirings for circuitry configured to detect X-rays are installed. For this reason, the photodiode array includes one or more active-area formation prohibited areas.
Accordingly, the active areas positioned closest to the end parts of the photodiode array are smaller than the other active areas. For this reason, the detection efficiency levels or the signal-to-noise (SN) ratios of the photodiodes having the active areas positioned closest to the end parts of the photodiode array may be degraded. Further, an artifact may occur due to the degradation of the detection efficiency levels and/or the SN ratios of the photodiodes.